SAN DIEGO — General manager Matt Klentak didn't have to look very far — only across the field and into the San Diego Padres' dugout — for a reminder of the impact that an August waiver trade can have on a Phillies team's chances of making the playoffs.

Ten years ago, on the second-to-last day of August, the Phillies traded for Matt Stairs. Now the Padres' assistant hitting coach, Stairs homered twice in 17 at-bats down the stretch to help the Phillies win the 2008 National League East title, then belted one of the most memorable homers in franchise history in the postseason.

On Friday, Klentak might have acquired this year's version of Stairs.

The Phillies placed a waiver claim on first baseman Justin Bour, then worked out a trade by shipping minor-league lefthander McKenzie Mills to the Miami Marlins, who agreed to pay a portion of the approximately $1 million left on Bour's $3.4 million salary this year. Bour is expected to join the Phillies here on Saturday and will be used by manager Gabe Kapler as primarily a lefthanded hitter off the bench.

"What we've been lacking is a big power hitter on the bench," Klentak said. Bour "fits our style of offense very well. He works counts, he takes walks, he hits the ball out of the ballpark. I think he's going to be a really good fit for this team."

The addition of Bour continues an extreme makeover of the Phillies' bench. For most of the season, Kapler's bench options have consisted mostly of inexperienced players, such as infielders Jesmuel Valentin and Mitch Walding and outfielder Dylan Cozens. But the team recently recalled fleet-footed outfielder Roman Quinn and pushed rookie shortstop Scott Kingery to the bench by trading for infielder Asdrubal Cabrera.

Bour, 30, is one year removed from a breakout season, in which he hit 25 home runs and slugged .536 in 377 at-bats for the Marlins. His numbers are down almost across the board this season. In 374 at-bats, he has 19 homers and is slugging only .412, tied for 49th among 75 National League hitters with enough at-bats to qualify for the batting title entering play Friday night.

But Bour figures to provide lefthanded power off the bench, in addition to being a notorious killer of the Atlanta Braves, who began Friday only one game behind the Phillies in the NL East. In 11 games against the Braves this season, Bour is 7 for 23 (.304) with two home runs and a 1.227 OPS. For his career, he's 48 for 159 (.302) with 13 homers and a 1.023 OPS in 54 games against Atlanta.

"I think it's worth noting that he's really hurt the Braves," Kapler said. "I think that matters."

Bour has hit the Phillies hard, too. He has four homers in 40 at-bats against them this season, and with six games remaining against the Marlins, it will help to not face him.

>>READ MORE: What the Justin Bour trade means for the Phillies in 2018 and beyond | David Murphy

Bour isn't eligible for free agency until after the 2020 season, which would seemingly increase the Phillies' options and flexibility at first base. But Klentak said the ability to control Bour beyond this season was secondary to the short-term impact that he could make.

"I think right now we're in a pennant race," Klentak said. "We've got six weeks to go in the regular season, and he can help us. I think that's the most important component."

If there's a question about Bour, it's how he might adjust to not getting regular at-bats after being an everyday player for most of the last four seasons in Miami. But Klentak and Kapler said that Bour's plate approach — he's known as a disciplined hitter who doesn't often chase pitches out of the strike zone — will enable him to be successful.

"I envision him being a dynamic, power-hitting weapon off the bench," Kapler said. "He knows how to look over the baseball. He attacks it when it's in the zone. He fouls balls off. He fights. He is a tough out."

To make room for Bour on the 40-man roster, the Phillies designated righthander Jake Thompson for assignment. When Bour arrives on Saturday, they will need to make another move to get him on the active roster. In all likelihood, they will option Kingery or fellow infielder J.P. Crawford to triple-A Lehigh Valley for a few weeks, until rosters expand on Sept. 1. Kingery is mired in an 0-for-20 funk and is one of only three qualified hitters in the majors with an OPS of less than .600.

Mills, 22, was promoted to double-A Reading only a few days ago, after posting a 3.51 ERA, 85 strikeouts, and 33 walks in 89 2/3 innings for Clearwater. A former 18th-round draft pick of the Washington Nationals, he was acquired by the Phillies last season in a trade for infielder Howie Kendrick.

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